Dispensable non-adhesive desiccated matrix system for insulating glass units

ABSTRACT

The present invention includes a method of making an edge assembly for an insulating glass unit, the edge assembly including a closed hollow spacer, the method comprising (1) dispensing a flowable desiccating matrix formulation onto a portion of the spacer which will be inside the hollow spacer when the spacer has been closed; (2) allowing or causing the formulation to solidify into a solid matrix and to detach from any attachment to the spacer; and (3) closing the spacer whereby the detached matrix will be retained within the spacer. The present invention includes a thermoplastic desiccating matrix formulation comprising about 80 to about 30 weight % of the formulation of a thermoplastic material; and about 20 to about 70 weight % of the formulation of an adsorbent component, wherein the adsorbent component includes a moisture adsorbing material and a volatile organic chemical adsorbing material, of which 0-50 weight % of the adsorbent component is the adsorbent of volatile organic compounds; wherein the formulation, when dispensed as a liquid onto an inner surface of an edge assembly and allowed to cool to ambient temperature, forms a solid matrix having an outer surface which does not adhere to the inner surface of the edge assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 60/096,490, filed Aug. 14, 1998.

FIELD OF THE INVENTION

The present invention relates to a desiccating matrix and a method forapplying the desiccating matrix in manufacturing insulating glass units.More particularly, the invention provides a non-adhering desiccatingmatrix for use with the insulating glass units, and includes a method ofapplying such non-adhering desiccating matrix to a spacer for an edgeassembly of an insulating glass unit.

BACKGROUND OF THE INVENTION

Insulating glass units (“IGUs”), made with at least two glass panelsarranged in spaced-apart relationship with an edge assembly to form anenclosed interior space, require the presence of a desiccant in theinterior space to avoid condensation of moisture or other volatilematerials due to the temperature difference between the inner and outerglass panels. Such condensation is generally referred to as “fogging” ofthe IGU. Moisture or materials such as volatile organic chemicals(“VOCs”) may remain in the interior space after manufacture or may seepinto the interior space during post-manufacture use. The moisture andVOCs may cause fogging in the interior space. The desiccant is providedto remove the moisture and/or VOCs from the interior space byadsorption. As used hereinafter, the terms “desiccating materials” and“desiccants” include adsorbents of both moisture and VOCs, except wherespecific adsorbents of moisture or VOCs are separately identified andlimited as to specific materials adsorbed.

In early IGUs, loose particles of desiccating materials in a containerwere placed in the interior space of the IGU, free of any matrix forholding together the desiccant particles. This resulted in problems suchas spillage of the desiccating material from the spacer, bead migrationand dusting, too-rapid adsorption of moisture resulting in prematuresaturation of the desiccant prior to assembly of the IGU and reducedlife expectancy or premature failure of the IGU, and included problemsin manufacture due to the size and nature of the particles of desiccantmaterials. An early example of such units may be found, for example, inU.S. Pat. No. 2,964,809. Similarly, in later IGUs, the loose desiccantmaterial was disposed in the body of the spacer itself, such as is shownin U.S. Pat. No. 3,998,680.

Later IGUs were provided with a desiccant dispersed within athermoplastic carrier, in which the thermoplastic was placed in theinterior space, as shown, for example in U.S. Pat. No. 3,758,996. In aneffort to simplify construction of the IGU, dimensionally stable sealantand spacer strips were developed. Such strips include an elongatedribbon of deformable sealant having an imbedded spacer means such as acorrugated metal strip. On the inner side of this strip is disposed adecorative facing which has impregnated therein a desiccant. Such asystem is sold as SWIGGLE® Seal, and is disclosed in U.S. Pat. No.4,431,691. Other IGUs include a spacer made of silicone or acrylic foamcontaining large quantities of a desiccant fill material, such as isshown in U.S. Pat. No. 4,950,344. An IGU with a spacer filled with adesiccating matrix is disclosed in U.S. Pat. No. 5,209,034.

Among other developments in this area are insulating glass units such asthose shown in U.S. Pat. No. 5,177,916 and the progeny thereof, in whicha U-shaped spacer is placed between glass panels to form an interiorspace, and an adhesive containing a desiccant is coated on the inside ofthe U-shaped spacer. A drawback of using mastics in an IGU like thatdescribed in U.S. Pat. No. 5,177,916 arises from limitations imposed bythe mastic. The material may soften such that it sags at thetemperatures to which the IGU is exposed in use. The desiccating masticmay evolve an excessive amount of water or organic vapors, which canresult in fogging. Thus, two-part, curing formulations have beenavoided, since curing reactions may evolve volatile byproducts. Themastic should be UV stable, since it will be directly exposed to UVradiation throughout its useful life. U.S. Pat. No. 5,510,416 describesa particular hot melt thermoplastic mastic. The hot melt mastic of U.S.Pat. No. 5,510,416 forms a coating on the interior of the U-shapedspacer of the IGU, so as to be retained thereon, to avoid the problem ofsagging and to prevent separation of the hot melt mastic from thespacer.

Another approach to providing desiccating materials in the interiorspace of IGUs is the DESI-ROPES® continuous desiccating cord. Such cordis provided in continuous, pre-extruded lengths, for insertion into thespacer during manufacture of the IGU. The DESI-ROPE® is believed to be acured EPDM elastomeric material impregnated with a desiccant. Thisproduct avoids some of the problems associated with the thermoplasticcompositions, but comes with its own set of drawbacks. Since the cord ispre-manufactured and contains desiccant, it must be handled and storedappropriately between the times of manufacture and use so as to avoidpremature moisture adsorption and saturation. According to themanufacturer's information, reels of the DESI-ROPE® material aresupplied in vacuum-sealed, moisture-proof foil bags which are in turnpackaged in high density polyethylene bags, and shipped in cardboardboxes. As a result, packaging for protecting this product frominadvertent exposure to moisture is an important issue, resulting inadditional costs and handling and storage precautions.

SUMMARY OF THE INVENTION

The present invention provides a method of applying a flowable,non-adhering desiccating matrix which overcomes the aforementionedproblems of the prior art. The present invention also provides aflowable, non-adhering desiccating matrix formulation. The presentinvention further provides an efficient method for forming an insulatingglass unit having a closed hollow spacer containing the thermoplasticdesiccating matrix, in which method the matrix formulation may be pumpedat or below the temperatures used for hot melt thermoplastics but doesnot adhere to the spacer when the molten desiccating matrix formulationsolidifies. Thus, a preferred formulation is characterized by thecombined features of being capable of being dispensed from, e.g., hotmelt equipment and of being non-adhering. The feature of being dispensedby hot melt equipment allows the matrix to be used in existing hot meltequipment. In an alternative embodiment, one or two part curabledesiccating mastic formulations may be used, provided such formulationsdo not result in an undue amount of evolved water or VOCs which couldresult in fogging. In such an alternative embodiment, the curablematerial may be pumped at room or ambient temperature. A two partformulation would be statically mixed at the point of application to thespacer. This alternative formulation, like the other formulationsdisclosed herein, preferably is non-adhering to the surfaces of thespacer when solidified.

The non-adhesion feature of the invention essentially allows the entiresurface of the desiccating matrix to be exposed to the atmosphere in theinterior space of the IGU. As a result of the increased surface area,the inventive thermoplastic desiccating matrix formulation featuresenhanced adsorption of moisture and volatile elements, thus contributingto a superior IGU which is easy to manufacture.

According to one aspect of the invention, a closed hollow spacer for aninsulating glass unit, is made by (1) dispensing a flowable desiccatingmatrix formulation onto a portion of the spacer which will be inside thehollow spacer when the spacer has been closed; (2) allowing or causingthe formulation to solidify into a solid matrix that will be detachedfrom the spacer; and (3) closing the spacer whereby the detached solidmatrix will be retained within the spacer.

According to another aspect of the invention, an insulating glass unitis made by assembling the closed spacer between two panes of glass. Anadhesive material may be provided between the spacer and the panes ofglass, and a sealing material may be provided between the spacer and/orthe panes of glass.

In one embodiment, the invention provides a method of making a closedhollow spacer for an insulating glass unit, comprising (1) dispensing aflowable desiccating matrix formulation onto a portion of the spacerwhich will be inside the spacer when the spacer has been closed; (2)allowing or causing the formulation to solidify into a solid matrix andto detach from any attachment to the spacer; (3) closing the spacerwhereby the detached matrix will be retained within the spacer.

In one embodiment, the invention provides a method of making aninsulating glass unit including at least two glass panels and a hollowspacer having an interior wall and separating the glass panels to forman interior space of the IGU, the hollow spacer retaining therein adesiccating matrix, comprising: (1) heating a desiccating matrixformulation to a temperature at which it is flowable; (2) dispensing theheated formulation onto the interior wall of the hollow spacer; (3)allowing the formulation to solidify to form a solid matrix; and (4)freeing the matrix from any adhesion to the spacer. The matrix may befreed from adhesion to the spacer by cooling or other means, such as bymechanically dislodging the solid matrix from any adhesion to thespacer.

In one embodiment, the invention provides a method of making aninsulating glass unit including at least two glass panels and a hollowspacer separating the glass panels, the panels and spacer forming aninterior space of the IGU, the hollow spacer retaining therein a soliddesiccating matrix, comprising: (1) heating a desiccating matrixformulation to a temperature at which it is flowable; (2) dispensing theheated formulation into the hollow spacer under conditions such that itforms a solid matrix which does not adhere to the spacer in use.

In one embodiment, the invention provides a thermoplastic desiccatingmatrix formulation including about 80 to about 30 weight % of theformulation of a thermoplastic material, wherein the thermoplasticmaterial is selected from the group consisting of ethylene vinyl acetatecopolymer, LLDPE, LDPE, styrenic thermoplastic elastomer,ethylene-methyl acrylate copolymer, and ethylene-acrylic acid copolymer;and about 20 to about 70 weight % of the formulation of an adsorbentcomponent, wherein the adsorbent component includes a moisture adsorbingmaterial and a volatile organic chemical adsorbing material, of which0-50% of the adsorbent component is the adsorbent of volatile organiccompounds.

In one embodiment, the invention provides a thermoplastic desiccatingmatrix formulation which, when dispensed as a flowable liquid onto aninner surface of an edge assembly and allowed to cool to ambienttemperature, forms a solid matrix having an outer surface which does notadhere to the inner surface of the edge assembly.

In one embodiment, the invention provides a thermoplastic desiccatingmatrix formulation comprising about 50 weight % of the formulation of anethylene vinyl acetate copolymer; and about 50 weight % of theformulation of an adsorbent component.

In one embodiment, the invention provides a desiccating matrixformulation consisting essentially of a combination of about 50 weight %of an ethylene vinyl acetate copolymer containing about 14 weight % ofvinyl acetate, and about 50 weight % of the formulation of a mixturecontaining about 85 weight % of 3A molecular sieve and about 15 weightpercent of 13X molecular sieve.

In one embodiment, the invention provides a desiccating matrixformulation comprising about 80 to about 30 weight % of the formulationof a curable material, wherein the curable material is selected from thegroup consisting of a one-part mixture comprising anisocyanate-terminated prepolymer and dibutyl tin dilaurate; a two-partmixture in which a first part comprises an isocyanate-terminatedprepolymer and dibutyl tin laurate and a second part comprises an activehydrogen compound; and a two-part mixture in which a first partcomprises diglycidyl ether bisphenol A and a second part comprises anepoxy curative; and about 20 to about 70 weight % of the formulation ofan adsorbent component, wherein the adsorbent component includes amoisture adsorbing material and a volatile organic chemical adsorbingmaterial, of which 0-50% of the adsorbent component is the adsorbent ofvolatile organic compounds.

The foregoing and other features of the invention are hereinafter morefully described and particularly pointed out in the claims, thefollowing description and the annexed drawings setting forth in detailcertain illustrative embodiments of the invention, these beingindicative, however, of but a few of the various ways in which theprinciples of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a prior art IGU.

FIG. 2 is a perspective, partial cut-away view of another prior art IGU.

FIG. 3 is a perspective, partial cut-away view of an IGU in accordancewith the present invention.

FIG. 4 is a schematic side elevational view of a roll-forming apparatus.

FIGS. 5A-5D are sequential schematic cross-sectional views of a strip ofspacer material at certain points during forming by the roll-formingapparatus of FIG. 4.

FIG. 6 is a cross-sectional view taken at line 6—6 of FIG. 5C, showingthe desiccating matrix formulation in accordance with the presentinvention flowing into the nascent spacer in accordance with the methodof the present invention.

FIGS. 7A and 7B are schematic cross-sectional views of, respectively, anupper edge and a lower edge of a spacer in an IGU containing thedesiccating matrix in accordance with the present invention.

DETAILED DESCRIPTION

In order to facilitate an understanding of the novel features of thepresent invention, reference is first had to an IGU of conventionaldesign, which includes a conventional thermoplastic desiccant mastic ormatrix, such as those illustrated in FIGS. 1 and 2. FIG. 1 is across-sectional view of a prior art IGU 10, as shown, for example inU.S. Pat. No. 5,177,916. The IGU 10 shown in FIG. 1 includes an edgeassembly having a U-shape channel 20 disposed between two glass panels14, which together create and define an interior space 22. The U-shapechannel 20 includes side walls 18 which are sealed to the glass panels14 by a moisture and/or gas impervious adhesive material 16, therebysealing the interior space 22 from the outside environment. Adesiccating mastic 26 is coated on the inside of the U-shape channel 20.The U-shape channel 20 continues around the entire outer edge and opensto the inside of the IGU. It is necessary for the desiccating mastic 26to remain adhered to the inside of the U-shaped channel 20, even atelevated use temperatures, in parts of the spacer which are inverted anddownwardly opening, or otherwise the desiccating mastic would fall outof the channel 20 and into the interior space 22. The use temperaturescan easily reach 85° C. At such temperatures, the desiccating mastic maysoften or lose its adhesion to the U-shaped channel, thereby protrudinginto the visible portion of the interior space of the IGU, in a failureknown in the art as “sag” or “sagging”. The prior art desiccating masticof the '916 patent, while being pumpable, is limited by the requirementsthat it remain coated on the edge assembly and that it not sag.

FIG. 2 is a perspective, partial cut-away view of another prior art IGU40. The IGU 40 shown in FIG. 2 includes an edge assembly having a closedspacer 42 which has a longitudinally extending slit 44 at the closure ofthe spacer 42. The spacer 42 is disposed between two glass panels 46, tocreate and define an interior space 48. The spacer 42 is sealed to theglass panels 46 by a moisture and/or gas impervious adhesive material50, thereby sealing the interior compartment 48 from the outsideenvironment.

The spacer 42 may be formed by a roll forming operation by which a flatstrip of material is gradually formed into the spacer 42. The final stepin formation of the spacer 42 closes the spacer, creating the slit 44. Aprefabricated extruded rope or cord 56 containing a desiccating materialis removed from a spool and inserted into the open end of the spacer 42.

The desiccating cord 56 suffers from the drawback that it must beprotected from moisture. Since the desiccating cord 56 is heavily loadedwith desiccant, the cord 56 must be protected from atmospheric moisturebetween the time it is manufactured and the time it is inserted into thespacer 42 and the IGU 40 is finally sealed from the external atmosphereduring the manufacturing process. Thus, the prior art desiccating cord56, while in some ways convenient, requires special handling between thetime it is manufactured and the time it is used, in consideration of itsinherent tendency to absorb moisture. For these reasons, as discussedabove, the DESI-ROPE® material is supplied in vacuum-sealed,moisture-proof foil bags which are in turn packaged in high densitypolyethylene bags, and shipped in cardboard boxes.

The present invention resolves the problems associated with theforegoing conventional desiccating materials for IGUs. In oneembodiment, the thermoplastic desiccating matrix formulation of thepresent invention may be dispensed by commercially available hot meltequipment during manufacture of the spacer for an IGU, contains a highloading of desiccant, and is retained within the closed spacer withoutadhering to the spacer. As a result of the high loading of desiccant andthe increased surface area exposed to the atmosphere in the interior ofthe IGU, the matrix maximizes the absorption of moisture and VOCs fromthe interior of the IGU. The feature of being dispensable from hot meltequipment results in easy application by means of conventional hot meltequipment and thus the matrix formulation is easily adaptable to manypresently existing IGU production lines. Another benefit is that sincethe desiccating matrix formulation may be stored in and dispenseddirectly from bulk containers such as drums, there is no need to takeadditional protective steps to keep the formulation from inadvertentexposure to moisture. The high loading of desiccant provides a long lifeto the IGU without necessitating use of large quantities of desiccatingmatrix. The fact that the desiccating matrix is retained within theconfines of a closed spacer avoids the requirement that the matrix becoated on the spacer, while avoiding the danger of failure by saggingduring use at normal use temperatures.

FIG. 3 is a perspective, partial cut-away view of an IGU in accordancewith the present invention. As shown in FIG. 3, the IGU of the presentinvention includes two glass panels 114 which are separated by an edgeassembly which includes a closed spacer 120. The spacer 120 has alongitudinally extending slit 121, which results when the spacer 120 isformed by roll forming a strip of metal to form the spacer 120. In theIGU 110, the spacer 120 is disposed between two glass panels 114, whichtogether form an interior space 122. The spacer 120 is sealed to theglass panels 114 by a moisture and/or gas impervious adhesive material124. Thus, the panels 114, the spacer 120 and the adhesive material 124together form the edge assembly which thereby seals the interior space122 of the IGU from the outside atmosphere. The hollow spacer 120includes walls which together define an interior cavity 128. Adesiccating matrix 132 is formed from a non-adhering, thermoplasticdesiccating matrix formulation, and is contained within the interiorcavity 128. The matrix 132 remains in a solid state and remainsnon-adhesive even at the maximum temperature to which an IGU is normallyexposed during use, e.g., at temperatures up to about 85° C.

As used herein, the term “closed” with respect to the spacer, means thatthe spacer is closed to a degree sufficient to retain the desiccatingmatrix within the confines of the spacer. The closed spacer is nothermetically sealed; on the contrary it should be in fluid communicationwith the interior space of the IGU, so as to provide contact between thedesiccant in the desiccating matrix and the moisture and/or VOCs whichmay be present in the atmosphere in the interior space of the IGU. Inaccordance with this definition, the space between the edges of thespacer which are brought together during the below describedroll-forming operation need only be sufficiently smaller than the sizeof the solidified desiccating matrix (or otherwise physically confined)such that the matrix will remain within the interior of the spacer atall times.

The spacer may be made by processes other than roll forming, and may beformed of materials other than metal. For example, the spacer may bemade of a thermoplastic or thermosetting material, which may be, forexample, formed by an extrusion process. In an extrusion process, thespacer may be closed prior to placement of the desiccating matrixformulation therein. In one embodiment, the spacer material is extrudedand is cooled by extrusion into a water bath. The desiccating matrixformulation may be applied through an injection nozzle which isconcentrically placed in the extrusion nozzle, whereby the desiccatingmatrix formulation is applied to the cooled, solidified spacer.

In one embodiment, the spacer is formed by a roll forming process, andafter being closed by a final roll forming step, the spacer is spotwelded to increase its torsional stability, in a welding step.

In one embodiment, the desiccating matrix formulation is applied at anelevated temperature and then solidified, as by cooling to ambienttemperatures. In this embodiment, a desiccating matrix formulation whichmay have some adhesive character at the elevated temperature at which itis dispensed, is allowed or caused to cool prior to coming into contactwith the spacer, so that it loses its adhesive character and does notstick to the spacer. The matrix formulation may be allowed, for example,to cool subsequent to being dispensed, but prior to contacting thesurface of the spacer by providing a sufficient distance between thelocation at which the matrix formulation exits the dispensing apparatusand the surface of the spacer so that by the time the matrix reaches thesurface of the spacer it has cooled and thereby at least partiallysolidified. The matrix formulation may be caused to cool subsequent tobeing dispensed, but prior to contacting the surface of the spacer byproviding a cooling device, such as a fan or a source of compressed airor other gas, which is directed upon the desiccating matrix formulationas it issues from the dispensing apparatus, thereby causing the matrixto cool and at least partially solidify, particularly at its surface.

The spacer 120 of the present invention preferably is made from a flatstrip of metal by a conventional roll-forming operation. In oneembodiment, the formulation which forms the matrix 132 is dispensed ontoan interior surface of the spacer 120 just before the final steps of theroll-forming operation, during which the spacer 120 is closed, formingthe slit 121. In another embodiment, the matrix 132 is formed when thematrix formulation is fed through the slit 121 after the spacer has beenclosed, such as by use of a nozzle that extends through the slit andinto the spacer. It is possible that the desiccating matrix formulationmay be applied to the strip at any point during the roll formingoperation. However, practical considerations, such as the possibility ofthe roll forming apparatus coming into contact with the matrix 132, maylimit the choice of application points.

FIG. 4 is a schematic side elevational view of a roll-forming apparatusthat may be used to roll-form a flat strip of material 150. Theroll-forming apparatus shown in FIG. 4 includes a series of pairs ofinteracting upper and lower rollers 180, 181, 182,183,184 and 185. Asthe strip 150 is fed into the roll-forming apparatus from left to right,the rollers 180-185 progressively bend the metal strip, converting iteventually from the initial flat strip into a fully formed spacer. It isnoted that additional pairs of roll-forming rollers may be required, inaddition to those schematically shown in FIG. 4.

FIGS. 5A-5D are schematic cross-sectional views of an exemplary strip ofspacer material at certain points during the roll-forming process. Whilethe exact sequence of steps involved in such a roll-forming operationare within the skill of and would be decided by a person of skill in theart, the sequence shown in FIGS. 5A-5D is illustrative of the process.As shown in FIG. 5A, a piece of metal feed material 150 in the form of aflat strip is provided, and is fed into a roll-forming apparatus. In afirst step, the outer ends of the material 150 are rolled or bentupwards to form edges 152 as shown in FIG. 5B. In a subsequent step,additional bends are made so as to roll up portions of the flat portionof the material 150 to form side walls 154 and inner walls 156, andleaving the outer wall 158, as shown in FIG. 5C. Finally, in subsequentsteps, the additional bends are brought to their final angles, therebyforming the side walls 154, the inner walls 156 and outer wall 158, fromthe material 150, thereby transforming the material 150 into a closedspacer 120.

FIG. 6 is a cross-sectional view taken at line 6—6 of FIG. 5C, showingone embodiment of the present invention, in which a desiccating matrixformulation is flowed into the nascent spacer. In the method of formingthe spacer and applying the desiccating matrix formulation thereto, theformulation may be dispensed as schematically shown in FIG. 6. In thisoperation, normally the nascent spacer 150 would be passed by thestationary dispensing apparatus 160, but the nascent spacer 150 may beheld stationary while the dispensing apparatus 160 is moved, or both maybe in motion. If the location at which the formulation exits thedispensing apparatus 160 is elevated further than is shown in FIG. 6,the matrix will be allowed to cool further prior to contacting thesurface of the spacer 150, all other things being equal. Similarly, ator near the location at which the formulation exits the dispensingapparatus 160, a cooling device may be provided. Such a cooling devicemay simply be a fan or other source of compressed air. The coolingdevice may also include a cooling belt, in which the desiccating masticformulation is initially applied to a cooled moving belt surface and issubsequently fed into the nascent spacer. Other means of cooling thedispensed formulation may be used.

The nascent spacer 150 should be passed by the dispensing apparatus 160at a speed which matches the flow rate of the formulation exiting thedispensing apparatus. In one embodiment, the spacer is moved at the rateof about 120 feet per minute. In one embodiment, the spacer isapproximately one-half inch (1.25 cm) wide, and the desiccant loading isdesirably about 3 grams per foot, for an IGU having a one-half inchspace between panes of glass. The amount of desiccant may be varied,depending on the volume of the space and the desired useful life of theIGU, among other factors, which would be known to a person of skill inthe IGU art. If the formulation comprises 50% desiccant, a total ofabout 6 grams per foot of the matrix should be provided for the spacer.Thus, the flow rate of the desiccating matrix formulation exiting thedispensing apparatus should be about 720 grams per minute.

In one embodiment, the desiccating matrix is dispensed such that itforms a bead approximately {fraction (3/16)} inch (4.8 mm) in diameter.It is recognized that due to the flowable, liquid character of thematrix formulation, the bead may collapse into a flattened, ellipticalor ovoid shape. Thus, the diameter is used as a convenient term only todescribe the approximate volume of the matrix if it maintained asubstantially round shape. Of course, the dispensing nozzle may have across-section other than circular, as may be desired in some instances.

FIGS. 7A and 7B are schematic cross-sectional views of, respectively, anupper edge and a lower edge of a spacer in an IGU containing thedesiccating matrix in accordance with the present invention. As shown inFIG. 7A, the matrix 132 rests upon the folded-in edges 152 of the spacer120. As shown in FIG. 7B, the matrix 132 rests upon an interior surface158 at the closed outer side of the spacer 120. These figures illustrateschematically that the matrix does not adhere to the surfaces of thespacer.

The matrix 132 preferably is formed by heating the thermoplasticdesiccating matrix formulation to a temperature in the range of about85° C. to about 200° C. and dispensing by pumping the formulation intothe partially formed cavity 128 of the spacer 120 during theroll-forming operation. The formulation has a sufficiently low viscositythat it may be pumped, for example, by standard hot melt dispensingequipment when heated to a temperature in the range from about 85° C. toabout 200° C. That is, the viscosity of the heated formulation is lessthan about 2,000 Kcps (thousand centipoise). In one embodiment, themaximum viscosity is about 1,750 Kcps. In one embodiment, the viscosityis in the range from about 50 to about 100 Kcps. In one embodiment, theviscosity is in the range from about 50 to about 500 Kcps. In oneembodiment, the viscosity is in the range from about 100 to about 1,000Kcps.

In addition to being dispensable by hot melt equipment, a preferredformulation has little or no adhesiveness even when molten. As usedherein, the terms “non-adhering”, “lacking adhesion”, and “not adhere”mean that the matrix does not form a significant adhesion to thesubstrate to which it is applied. The formulation may have an initialadherence on contact, but loses the adherence when the formulation issolidified. In fact, initial adhesion may be desirable for drawing theformulation with the spacer during dispensing. A simple test todetermine a lack of adhesion is described in more detail below.

The formulation preferably should be non-adhering at temperatures about10-15° C. lower than the minimum temperature at which it would bedispensed by hot melt equipment. It is recognized that the formulationmay have a small degree of adhesiveness at the application temperature,but it is contemplated that at least upon cooling below its softeningpoint, little or no adhesiveness will remain. Thus, once the matrix 132has formed when the formulation is allowed to cool, it should either notadhere to the interior of the spacer 120 at all, or it should adhere solittle that it will release from the spacer 120 when the spacer isrotated about its longitudinal axis by 90° from its position shown inFIG. 7B and gently impacted with a force that will not damage the IGU.

Such gentle impact may involve tapping the spacer manually, tapping thespacer against a solid structure such as a floor or table, the shakingor jostling that arises from normal handling of the spacer prior to andduring installation in an IGU, or the bending of the spacer to fit theIGU during manufacture of the IGU. In experiments, it was demonstratedthat simply allowing the spacer with the initially-adhering desiccatingmatrix thereon to drop from a height of approximately 6 inches was asufficient force to separate an initially-adhering desiccating matrix.As stated above, it is preferred the desiccating matrix not adhere atall, but in some cases the desiccating matrix may adhere temporarily.The terms “adhere temporarily” or “initially-adhering”, when applied toa desiccating matrix formulation in accordance with the presentinvention, mean that with application of a gentle impact, approximatelyequivalent to dropping the spacer with the desiccating matrix thereonfrom a height of about six inches, the desiccating matrix is freed orreleased from any adhesion to the spacer.

In a simple laboratory measurement of the force needed to free adesiccating matrix having a preferred formulation in accordance with theinvention from its initial adhesion to a substrate, the followingprocedure was used. To a strip of metal weighing about 12 grams anddisposed horizontally was applied a 6 gram bead of a desiccating matrix.Upon cooling, when the strip was turned from the horizontal to avertical position, the desiccating matrix did not spontaneously releasefrom the substrate. Thus, the desiccating matrix could be said to haveinitially adhered to the substrate. The test strip was raised six inchesabove the floor and dropped, whereupon the desiccating matrix wasdislodged from the substrate.

The matrix 132 may be formed of a thermoplastic material which sets uprapidly once it cools below the application temperature. Thus, athermoplastic material is preferred which has a melting point or meltingrange close to the hot melt application temperature range of about 85°C. to about 200° C. The thermoplastic material used for the formulationpreferably has a melt viscosity which is very low, so that it is easilyflowable once it is melted. On the other hand, the formulationpreferably sets up rapidly to form the matrix 132 when it cools.Preferably, since the lowest application temperature is generally about85° C., the matrix 132 will be fully set up and will have lost anyadhesiveness by the time it cools to a temperature in the range of about70° C. to about 75° C. This is in accord with the feature that thematrix 132 not develop any adhesiveness when reheated to and held attemperature as high as 70° C. for an extended period of time.

Alternatively, the matrix 132 may be made from a flowable polymericmatrix formulation which is a thermoset or which cures afterapplication. Examples are given in the formulations section below. Withthese formulations, the flowable polymeric matrix is usually applied atabout room temperature, or the ambient temperature of the manufacturingenvironment. The polymerization reaction of the flowable polymericmatrix causes the matrix to solidify, as opposed to the cooling of athermoplastic formulation, which causes the solidification of thoseformulations.

Even though the matrix 132 may be heavily filled with desiccant, apreferred formulation is flowable and therefore dispensable attemperatures at which hot melt materials are normally dispensed. In oneembodiment, the matrix 132 is a non-adhesive solid when applied to anIGU and cooled to a temperature in the range of about 70° C. to about75° C. In one embodiment, the matrix 132 after cooling to a temperaturein the range of about 70° C. to about 75° C., is a firm, non-tackysolid. The matrix 132 is physically retained within the confines of thespacer 120 due to the fact that the spacer 120 is closed. For thisreason, it is not necessary for the matrix 132 to adhere to the insideof the spacer 120. In fact, it is desired that the matrix 132 not adhereto the inside of the spacer 120, since as a result of not adhering, theentire surface of the desiccating matrix 132 is exposed to theatmosphere in the interior space of the IGU, thereby to provide maximumadsorption of moisture and VOCs. Thus, the matrix 132 features thebenefits of containing a high loading of desiccant, being dispensable bycommercially available hot melt equipment or the like, and beingnon-adhering. In addition, the matrix 132 does not develop adhesion evenat temperatures up to about 70° C. for extended periods. Thus,essentially the entire surface area of the matrix 132 remains exposed tothe atmosphere in the interior space 122 of the IGU.

Since the formulation which forms the matrix 132 can be dispensed fromcommercially available hot melt equipment or the like, it can be shippedand stored as a solid in sealed drums, then be melted and dispensed intothe edge assembly of the IGU 110 when needed. This benefit reduces to aminimum the time the matrix 132 is exposed to atmospheric moisture. As aresult, the bulk formulation does not require any special protectivemeasures, other than storage in the closed drums in which it may beshipped and from which it may be dispensed, to avoid exposure to theopen atmosphere or other sources of moisture prior to use. When readyfor use, the drum may be opened, attached to the hot melt pumpingequipment, the bulk material heated to melting and thence pumpeddirectly to the spacer into which it is to be dispensed. The formulationforming the matrix 132 is applied to the spacer soon or immediatelyafter the drum is opened and just prior to final closure of the IGU.Therefore, there is no concern about exposure of the desiccant to theatmosphere outside the IGU prior to use.

An additional benefit of the non-adhering feature of the presentinvention is the ease of cleaning the dispensing equipment following itsuse. Most adhesive materials are difficult to clean, requiring use ofsolvents, heat and various physical efforts to remove the adhesivematerials after use.

As used herein, a formulation is considered “dispensable by hot meltequipment” if it can be dispensed by heating, melting and pumping bymeans of standard, commercially available hot melt dispensing equipment.The criteria of dispensability with conventional industrial hot meltapplicators allows the formulation of the present invention to be usedby existing equipment. Thus, the present method of applying thedesiccating matrix to an IGU may be easily introduced into and adaptedfor use in many existing IGU production lines.

To assure that the formulation will provide the maximum surface area tothe atmosphere inside the IGU, in one embodiment, the formulation shouldat minimum develop no adhesion and not sag when installed in the IGU andmaintained at a temperature of at least 60° C. (140° F.) for acontinuous period of at least 14 days. In one embodiment, theformulation will withstand at least 70° C. (158° F.) for at least 14days without developing a significant amount of adhesion or sagging. Inone embodiment, the formulation will withstand at least 70° C. (158° F.)for at least 1 month without developing any adhesion or sagging.

Methods

The present invention provides a method of making an edge assembly foran insulating glass unit. A preferred method involves (1) dispensing aflowable desiccating matrix formulation onto a portion of the spacerwhich will be inside the hollow spacer when the spacer has been closed;(2) allowing or causing the formulation to solidify into a solid matrixand to detach from any attachment to the spacer; and (3) closing thespacer whereby the detached matrix will be retained within the spacer.

More particularly, the thermoplastic desiccant-loaded formulation isheated to a temperature in the range of about 85° to about 200° C. anddispensed onto a portion of the spacer which will be inside the hollowspacer when the spacer has been closed. The formulation is cooled into asolid desiccating matrix and is detached from the spacer.

The process of forming a spacer for an IGU by a roll forming process iswell known in the art, and has been generally described above. Simplystated, a strip of material, usually a metal, is passed through a seriesof rollers which gradually bend and fold portions of the strip into adesired shape, in this case as a spacer for an IGU. The desiccatingmatrix may be applied at any convenient point during the roll formingprocess. It will generally be preferred to apply the matrix at a timewhen the spacer has a U-shape, or when the sidewalls of the spacer havebeen formed, to avoid the necessity of applying further rollers to thenascent spacer in the proximity of the matrix. Since the preferredmatrix does not significantly adhere to the surface of the spacer,applying the matrix at a time when the spacer has a U-shape avoids thepossibility of the matrix escaping the spacer during subsequent rollforming operations. Subsequent to application of the matrix, the spaceris subjected to further roll forming operations to substantially closethe spacer, forming for example a box-like enclosed spacer like thatshown in FIG. 3 which retains the matrix within the box-like spacer. Theenclosure needs to be closed to a degree which, at a minimum, retainsthe matrix therein, but which allows the desiccant to be exposed to theinterior atmosphere of the IGU.

The enclosure is formed such that the interior of the hollow spacer isin fluid communication with the interior space of the IGU. Thecommunication may be by way of the longitudinal slit 44, or may be bymeans of other openings made in the spacer to provide the communication.

The final desired shape may be shaped as a closed “C” or may be morebox-like, in which the sides of a U-shaped intermediate are bent inward,towards one another, to form a closed box-like spacer, an example ofwhich is shown in FIG. 5D. The box-like spacer is the preferred spacerfor use with the present invention. However, other shapes may be usedwithin the scope of the invention. The spacer retains the desiccatingmatrix as a result of its physical shape, as opposed to the desiccatingmatrix being held in position by adhering to the spacer.

As described above, the melted formulation is dispensed into a nascentspacer, during the process of roll forming a strip of metal into aspacer for an IGU. The spacer may be made by other processes, but a rollforming process is preferred.

In one embodiment, the actual dispensing temperature is in the rangefrom about 85° C. to about 200° C. (about 185° F. to about 248° F.). Inanother embodiment, the actual dispensing temperature is in the rangefrom about 90° C. to about 140° C. (about 194° F. to about 284° F.). Inanother embodiment, the actual dispensing temperature is in the rangefrom about 85° C. to about 130° C. (about 185° F. to about 266° F.). Inanother embodiment, the actual dispensing temperature is about 110° C.(about 230° F.). In another embodiment, the actual dispensingtemperature is about 115° C. (about 239° F.). In another embodiment, theactual dispensing temperature is about 130° C. (about 266° F.). Inanother embodiment, the actual dispensing temperature is about 140° C.(about 284° F.). In another embodiment, the actual dispensingtemperature is about 160° C. (about 320° F.). In another embodiment, theactual dispensing temperature is about 180° C. (about 356° F.). Inanother embodiment, the actual dispensing temperature is about 200° C.(about 392° F.). Higher actual dispensing temperatures may be used, butare not generally favored for safety and/or energy conservation reasons.

Once the formulation has been applied to the nascent spacer, it isallowed to cool to form the matrix. At the same time, the remainingsteps of forming the spacer may be completed. The completed spacer mayhave an adhesive applied to the appropriate outer surfaces and the IGUassembled in known fashion thereafter.

In other embodiments, the flowable desiccating matrix formulation may beapplied at ambient temperatures. In these embodiments, the formulationis a curable formulation and may be a thermosetting formulation. Inthese embodiments the formulation may comprise a one-part curableformulation or a two-part curable formulation. Examples of suchformulations are provided below. In these embodiments, the desiccatingmatrix formulation would be flowable and capable of being pumped byordinary equipment, but would not require heating, as would hot melttype formulations.

In one embodiment the matrix does not adhere at any time to the spacer.In some embodiments, a small degree of initial adhesion may be observed.As needed, the matrix may be released by simply rotating the spacer ortapping the spacer with a hard object, such as tapping the spaceragainst the floor, a wall or some other object. Due to the lowadhesiveness of the matrix, very little force is required to dislodgethe matrix in the event that it temporarily adheres to the inner wallsof the spacer.

In one embodiment, the method places a thermoplastic desiccating matrixformulation into an edge assembly for an insulating glass unit. The edgeassembly together with at least two glass panels forms the interiorspace of the insulating glass unit. The edge assembly includes a hollowspacer having interior walls in fluid communication with an atmospherewithin the interior space of the IGU. In another embodiment, the methodincludes (1) heating a thermoplastic desiccating matrix formulation to atemperature in the range of about 85° to about 200° C., (2) dispensingthe formulation onto a portion of the interior walls of the spacer; (3)allowing the formulation to cool to a temperature at which theformulation solidifies to form the matrix; and (4) freeing the matrixfrom any adhesion to the interior walls.

In one embodiment of the present invention, the method is used formaking an insulating glass unit including at least two glass panels anda hollow spacer having an interior wall and separating the glass panelsto form an interior space of the IGU, the hollow spacer retainingtherein the thermoplastic desiccating matrix. In this embodiment, themethod includes (1) heating a thermoplastic desiccating matrixformulation to a temperature at which it is flowable; (2) dispensing theformulation onto the interior wall of the hollow spacer; (3) allowingthe formulation to cool to a temperature at which it solidifies to formthe matrix; and (4) freeing the matrix from any adhesion to the spacer.

In one embodiment, the invention provides a method for making aninsulating glass unit, including at least two glass panels and a hollowspacer separating the glass panels, the panels and spacer forming aninterior space of the IGU, the hollow spacer retaining therein adesiccating matrix. In this embodiment, the method includes (1) heatinga thermoplastic desiccating matrix formulation to a temperature at whichit is flowable; and (2) dispensing the formulation into the hollowspacer under conditions such that it forms a solid matrix which does notadhere to the spacer.

Formulations

THERMOPLASTIC POLYMERIC MATERIAL

In one embodiment, the inventive thermoplastic desiccating matrixformulation comprises from about 30 weight % to about 80 weight % of athermoplastic polymeric material. In another embodiment, the inventiveformulation comprises from about 40 weight % to about 60 weight % of athermoplastic polymeric material. In another embodiment, the inventiveformulation comprises from about 45 weight % to about 55 weight % of athermoplastic polymeric material. In another embodiment, the inventiveformulation comprises about 50 weight % of a thermoplastic polymericmaterial. In another embodiment, the inventive formulation comprises atleast about 50 weight % of a thermoplastic polymeric material.

In various embodiments, the thermoplastic polymeric material may be oneor more of poly alpha olefins (poly-α-olefins) and copolymers of polyalpha olefins, polyethylene and copolymers of polyethylene;polyacrylates and polymethacrylates; polyimides; polycarbonate;polyesters; polystyrene and copolymers of polystyrene; polyvinylchloride and copolymers of polyvinyl chloride; polyvinylidene chlorideand copolymers of polyvinylidene chloride; polymethylene oxide;polyethylene oxide; polypropylene oxide; polyphenylene oxide;thermoplastic elastomers and ionomers; polyvinyl acetate; polybutadiene;and elastomers such as natural and synthetic rubbers.

More specifically, polymers useful in this invention may include:polymers of ethylene, such as linear low density polyethylene (LLDPE)and low density polyethylene (LDPE); polyethylene co-vinyl acetate;polyethylene co-acrylic acid (or acrylic acid esters i.e. methyl, ethyl,butyl); polyethylene co-vinyl alcohol; polyethylene co-maleic anhydride;polypropylene; polypropylene co-alpha olefin (i.e. ethylene, butylene,hexene); polybutylene, polyisobutylene, and other polyalphaolefins (i.e.1-hexene, 1-octene); polyamides (typically polyamides of fatty aciddimers); polyesters (from dibasic acids or from (alpha)-(omega) hydroxyacids); polyethylene oxide; polydimethylsiloxane polymers; polystyrene,poly-alpha-methyl styrene, and polyvinyl toluene; PVC and PVC copolymerswith acrylic acid and/or acrylic acid esters; polyurethanethermoplastics; styrenic thermoplastic elastomers; polyvinyl acetate;polybutadiene; and natural and synthetic rubber. Specific formulationstested are shown in the Examples.

The commercial materials used in the examples are identified as follows.A polybutylene designated DP 8510 is available from Shell Chemical Co.Ethylene vinyl acetate copolymers designated ESCORENE®D are availablefrom Exxon Chemicals with various vinyl acetate content. ESCORENESUL7710 is an EVA containing about 18 weight % vinyl acetate. ESCORENE®MVO 2514 is an EVA containing about 14 weight % vinyl acetate. ESCORENE®MVO 2520 is an EVA containing about 20 weight % vinyl acetate. ESCORENE®MVO 2528 is an EVA containing about 28 weight % vinyl acetate. A LLDPEdesignated GA 594 available from Equistar. A styrenic thermoplasticelastomer designated KRATON® D 1107 is available from Shell Chemical Co.An ethylene-methyl acrylate copolymer designated Optima TC 120 isavailable from Exxon Chemicals. An ethylene-acrylic acid copolymerdesignated Allied AC 617 is available from Allied. A process oilplasticizer designated SUNPAR® 2280 is available from Sun Chemical Co. Afatty acid dimer polyamide designated VERSAMID® 757 is available formHenkel. A hydrogenated rosin ester designated FORAL® 85 is availablefrom Hercules.

While the useful molecular weight naturally varies according to thespecific polymer, the polymeric materials useful in the presentinvention typically include materials having a molecular weight aboveabout 2500 g/mol, but may include materials of less than 2500 g/mol. Inone embodiment, the weight average molecular weight is in the range fromabout 2,000 to about 3,000 g/mol. In another embodiment, the weightaverage molecular weight is in the range from about 2,500 to about 5,000g/mol. In another embodiment, the weight average molecular weight is inthe range from about 2,000 to about 100,000 g/mol. In anotherembodiment, the weight average molecular weight is in the range fromabout 2,500 to about 25,000 g/mol. In another embodiment, the weightaverage molecular weight is in the range from about 2,000 to about 6,000g/mol. In another embodiment, the weight average molecular weight isabout 2500 g/mol. In each of the foregoing embodiments, the range ofmolecular weights in the thermoplastic polymeric material preferablyshould be as narrow as possible, thereby contributing to a sharp meltingpoint.

The thermoplastic material used in the foregoing formulations preferablyshould be moisture-permeable. As used herein, the termmoisture-permeable means that the material has a moisture permeabilityof at least about 1 gm/24 hr/1 ml/mil at 37.8° C. (100° F.), 90%relative humidity, as determined by ASTM E-96-66 Method E. In oneembodiment, the thermoplastic material has a moisture permeability of atleast about 10 gm/24 hr/1 ml/mil at 37.8° C. (100° F.), 90% relativehumidity, as determined by ASTM E-96-66 Method E. In one embodiment, thecurable polymeric material has a moisture permeability of at least about10 gm/24 hr/1 m²/mil at 37.8° C. (100° F.), 90% relative humidity, asdetermined by ASTM E-96-66 Method E. In one embodiment, thethermoplastic material has a moisture permeability of at least about 30gm/24 hr/1 m²/mil at 37.8° C. (100° F.), 90% relative humidity, asdetermined by ASTM E-96-66 Method E. In one embodiment, the curablepolymeric material has a moisture permeability of at least about 30gm/24 hr/1 m²/mil at 37.8° C. (100° F.), 90% relative humidity, asdetermined by ASTM E-96-66 Method E.

Adsorbent Material

In one embodiment, the inventive thermoplastic desiccating matrixformulation comprises from about 70 weight % to about 20 weight % of anadsorbent material which includes a moisture absorbing material and avolatile organic chemical absorbing material. In another embodiment, theinventive formulation comprises from about 60 weight % to about 40weight % of an adsorbent material. In another embodiment, the inventiveformulation comprises from about 55 weight % to about 45 weight % of anadsorbent material. In another embodiment, the inventive formulationcomprises about 50 weight % of an adsorbent material. In anotherembodiment, the inventive formulation comprises at least about 50 weight% of an adsorbent material.

The adsorbent material may be one or more of the known moistureadsorbing materials, in combination with one or more of the known lowmolecular weight organics (including, but not limited to, VOCs)absorbing materials. The adsorbent material may be one or more ofmolecular sieve, diatomaceous earth, zeolite (e.g., chabasite,gumerinite, levynite, erinite, mordenite and analcite) activated carbon,activated alumina, silica gel, silica-magnesium gel, silica-alumina gel,and calcium oxide, each of which are capable of absorbing both moistureand VOCs.

In one embodiment, the adsorbent material is molecular sieve. Molecularsieve is a particularly effective absorbent of both moisture and lowmolecular weight organics. In one embodiment the molecular sieve is amixture of 3A and 13X sieve. The 3A molecular sieve is preferred foradsorption of water, and is capable of adsorbing some VOCs. The 13Xmolecular sieve also adsorbs VOCs and water. In one embodiment, themolecular sieve may comprise 4A and/or 5A molecular sieves, instead ofor in addition to the 3A and 13X molecular sieves. In one embodiment,the adsorbent component is exclusively 3A molecular sieve. In anotherembodiment, about 95 weight % 3A molecular sieve and about 5 weight %13X molecular sieve are included. In another embodiment, about 90 weight% 3A molecular sieve and about 10 weight % 13X molecular sieve areincluded. In another embodiment, about 80 weight % 3A molecular sieveand about 20 weight % 13X molecular sieve are included. In anotherembodiment, about 70 weight % 3A molecular sieve and about 30 weight %13X molecular sieve are included. In another embodiment, about 65 weight% 3A molecular sieve and about 35 weight % 13X molecular sieve areincluded. In another embodiment, about 60 weight % 3A molecular sieveand about 40 weight % 13X molecular sieve are included. In anotherembodiment, approximately equal weights of the 3A and 13X molecularsieves are included. In one embodiment, the mixture contains from about80 weight % to about 95 weight % of 3A molecular sieve. Similar rangesof amounts of 4A and 5A molecular sieve may be used.

Tackifiers

Tackifiers are a class of chemicals used to modify the viscoelasticproperties of a polymer system. Tackifiers can be made from resinsobtained from petroleum feedstocks or from natural raw materials such aswood rosin. Resins may be made from monomers obtained from petroleumfeedstocks, such as styrene or piperline. A particularly useful resin isENDEX® 160 or 155, which is a poly-α-methyl styrene available fromHercules. Resins are typically lower in molecular weight than polymers,but may have higher molecular weight than polymers with which the resinsare used. Resins typically have a softening point or range as opposed toa sharp melting point such as is observed with crystalline materials.

In one embodiment, the desiccating matrix formulation comprises a resinmixed with molecular sieve. The ratio of resin to molecular sieve may besimilar to those disclosed above with respect to thermoplastic polymers.Resins are preferably added to thermoplastic polymers to modify theviscoelastic properties thereof, but may in some cases be used alone.Thus, the tackifier could replace all of the thermoplastic in thedesiccating matrix formulation of the present invention.

Tackifiers which may be used with the present invention includehydrocarbon resins prepared from C5 monomers, hydrocarbon resinsprepared from C9 monomers, hydrocarbon resins prepared from both C5 andC9 monomers, terpene hydrocarbon resins, phenolic tackifying resins,terpene-phenolic tackifying resins, dicyclopentadiene tackifying resins,pure monomer tackifying resins (styrene and styrene derivatives),glycerol esters of rosin, and pentaerythritol esters of rosin. Thetackifier may be a hydrogenated rosin ester, for example an ester ofabietic acid.

The tackifier may be present in the desiccating matrix formulation in anamount ranging from 0% to 40% by weight of the formulation. In oneembodiment, the formulation comprises about 5% by weight of thetackifier. In one embodiment, the formulation comprises about 25% byweight of the tackifier. In one embodiment, the formulation comprisesfrom about 5% by weight to about 25% by weight of the tackifier.

Waxes

Waxes are a class of compounds having viscosities quite susceptible tochanges in temperature. Waxes are classified by their origin, animal,vegetable, mineral, and synthetic. Waxes are often used in hot meltformulations to reduce viscosity at elevated temperatures. In oneembodiment, the desiccating matrix comprises a single wax mixed withmolecular sieve. The ratio of wax to molecular sieve may be similar tothose disclosed above with respect to thermoplastic polymers. In thepresent invention, waxes may be substituted for the thermoplasticpolymer component, or may be added to the thermoplastic polymer tomodify the properties thereof.

Waxes which are useful in the present invention include animal waxes,beeswax, vegetable waxes, carnauba wax, Japan wax, mineral waxes, montanwax, paraffin wax, synthetic wax, microcrystalline wax, polyethylenewaxes, and polyethylene glycol waxes.

In one embodiment, the desiccating matrix formulation comprises mineralwax and molecular sieve. In another embodiment, the desiccating matrixformulation comprises paraffin wax and molecular sieve. In anotherembodiment, the desiccating matrix formulation comprises polyethylenewax and molecular sieve. In another embodiment, the desiccating matrixformulation comprises polyethylene glycol wax and molecular sieve.

The thermoplastic component of the desiccating matrix formulation may beentirely replaced by a wax. In the desiccating matrix formulation, a waxmay be present in an amount ranging from 0% to about 45% by weight ofthe formulation. In one embodiment of the desiccating matrixformulation, a wax is present in an amount of about 35% by weight of theformulation. In one embodiment, a wax is present in an amount of about5% by weight of the formulation. In one embodiment of the desiccatingmatrix formulation, a wax is present in an amount ranging from about 6%by weight to about 35% by weight of the formulation.

In general, addition or substitution of a wax is preferable to additionor substitution of a tackifier in the desiccating matrix formulation ofthe present invention.

Plasticizer

Plasticizers are added to polymers to facilitate compounding and toimprove flexibility. In one embodiment, the thermoplastic desiccatingmatrix formulation includes a small amount of a plasticizer, in therange of about 1 weight % to about 5 weight %. In one embodiment, theamount of plasticizer is in the range from about 0.1 weight % to about 1weight %. In another embodiment, the amount of plasticizer in is therange from about 1 weight % to about 2 weight %. In another embodiment,the formulation includes no plasticizer. If any amount of plasticizer isused, it should not result in adhesion of the to the spacer or the edgeassembly at normal application or use temperatures. In other words, itshould be non-adhering as defined herein. As shown in the examples, aplasticizer such as SUNPAR® 2280 may be used without causing adhesion ofthe desiccating matrix, but may cause some amount of fogging when testedin the stringent pot fogging test described below.

Plasticizers which may be used in the thermoplastic desiccating matrixformulation in accordance with the present invention include: phthalate,adipate, and sebacate esters, aryl phosphate esters, petrolatum,paraffinic process oil, napthenic process oil, and aromatic process oil.

Other Additives

The inventive thermoplastic desiccating matrix formulation may alsocontain additives known in the art, such as antioxidants, colorants,fillers, UV and thermal stabilizers and rheological modifiers, providedthat they do not result in adhesion of the formulation to the spacer oredge assembly at normal use temperatures. The fillers which may be usedinclude: plastic fiber, calcium carbonate, talc, clay, silica, bariumsulfate, ground rubber and plastic scrap, oxides of zinc or titanium,carbon black, and wood or nut shell flour.

The amounts of other additives which may be included in the desiccatingmatrix formulation of the present invention are substantially similar tothe amounts added to similar formulations, as would be understood by aperson of skill in the art. The desiccant or adsorbent material used inthe present invention provides many of the benefits of a filler, makingit unnecessary to include an additional, separate filler.

In one preferred embodiment, plastic fibers, for example KEVLAR® brandplastic fibers are added to the formulation. In one embodiment, about0.2% by weight of the formulation of KEVLAR® brand plastic fibers areadded to the formulation. The amount of such fibers added may range fromabout 0.05% to about 0.5% by weight of the formulation. Such plasticfibers fe added to avoid or prevent the flowable material from becoming“leggy” during application in the flowable state of the desiccatingmatrix formulation, i.e., not breaking cleanly when the flow of thematerial is stopped.

Test Procedures

Canadian Volatile Fogging Test

As discussed in the foregoing, insulating glass units are subject tofogging if excessive amounts of moisture and/or VOCs are present in theinterior space of an IGU defined by the glass panels and the edgeassembly. The present desiccating matrix formulation is free of suchfogging, based upon standard tests. The preferred standard in theindustry is promulgated by the Canadian General Standards Board, as partof CAN/CGSB-12.8-97 for Insulating Glass Units, par.3.6.5, requires thatIGUs shall show no evidence of fogging or residue when tested and viewedin accordance with par. 4.3.2, the volatile fogging test. Par. 4.3.2“Volatile Fogging Test” sets forth the standard test for fogging inIGUs. The test procedure is briefly described as follows.

In the volatile fogging test, a pair of IGUs are set up in a testchamber. The inside of the test chamber is maintained at a temperatureof 60±2° C., and is provided with a small circulating fan to maintain auniform temperature in the chamber. The upper edge of the IGU ismaintained at a temperature of 58±2° C., and the circulating fan isoperated so as to maintain a temperature gradient from the upper edge tothe lower edge of the IGU is no more than 12° C.

A cooling plate having water circulating therein is attached to onepanel of the IGU, for the purpose of cooling the panel and establishinga temperature gradient between sides of the IGU similar to that to whichan IGU in actual use might be exposed. The cooling water is maintainedat a temperature of 22±2° C., at the point it exits the cooling plate.

The IGUs to be tested are exposed to these conditions for a period ofseven days. At the end of this period, the IGUs are removed, cleaned,and mounted in a viewing box such that an observer may view the unitthrough the surface on which the cooling plate was placed during thetest. The unit is observed for any evidence of fogging. Any foggingobserved constitutes failure. In the present specification, the absenceof fogging, or the criteria of being free of fogging means that the IGUin question passes this fogging test.

Pot Fog Test

An alternative fog test is known as the pot fog test. The pot fog testis more stringent that the Canadian fog test. The pot fog test indicatesthe tendency of a material to cause an oily deposit on glass, in aphenomenon also referred to as fogging. Fogging results in poorvisibility through the glass caused by the condensation on the glasssurface of volatile components in the material.

The pot fog test is conducted generally as follows. Clean, oil-freeglassware must be used, and a blank determination should be run toprovide a check on the glassware. Weigh 30 grams of test material into apetri dish. Place the petri dish in the bottom of a 1-liter beaker, witha thermocouple under the petri dish. Place the 1-liter beaker into astainless steel 2-liter beaker containing sufficient heating media, suchas DOW 550 fluid to cover at least one half the vertical height of the1-liter glass beaker. Place a gasket made of blotter paper or othersuitable material over the mouth of the beaker, and place a pane ofglass over the blotter paper. The blotter paper should have an openingwhich is approximately ¼ inch smaller in diameter than the diameter ofthe 1-liter glass beaker. Insert a thermometer into the heating media.Place a condenser coil on the glass pane over the opening in the blotterpaper. Place the stainless steel beaker on a hot plate and beginheating. The temperature should be adjusted such that the temperaturesensed by the thermocouple is 85° C. to 90.6° C. (185° F. to 195° F.). Awater supply is connected to the condenser coil, and water at atemperature of 21° C.-24° C. (700-750° F.) is passed through thecondenser coil. The test is continued for a period of 16 hours.

At the end of the test period, the glass plate is removed and observedfor the presence of any condensation or fog, by noting the amount ofhaziness at oblique angles against a dark background. Samples arevisually rated as having none, slight, medium or heavy fog. It ispreferred that the samples display no fog, but very slight fogging maybe acceptable.

Adhesion Test

The purpose of the adhesion test is to determine if a hot-appliedthermoplastic formulation will adhere to a specified clean substrate.The choice of substrates actually tested is determined by the particularend use of the matrix, and the material to which the matrix is to beapplied in actual use. Application temperature is similarly governed bythe melt properties of the matrix and the end use. A constanttemperature throughout the application must be maintained, for purposesof test uniformity. Because the degree of adhesion depends upon thecontact area between the matrix and the substrate, the matrix ispreferably applied through an orifice sized to produce a bead ofapproximately {fraction (3/16)}″ (0.1875 in, 4.76 mm) diameter on thesubstrate. The exact size of the orifice may be different, but should beconstant to provide valid comparisons between matrices.

Adhesion Test Equipment

Adhesive panels—Typically 1.5″-12″ of specified substrate. Typicalsubstrates include:

Electrolytic tin plated steel (T-4 temper, #5 finish)

Type 201 or 430 Stainless steel (#1 annealed, BA finish)

3003 Alloy Aluminum (H-19 temper)

The selected substrate may be fastened to wooden carriers for ease ofcleaning, handling and application of adhesive.

A typical applicator which is capable of maintaining a constanttemperature is a melt flow index tester having a 0.1875″ orifice. A pipenipple with cap having a 0.1875″ orifice drilled in the cap and a solidshaft snugly fitting into the internal diameter of the pipe nipple mayalso be used. Typical application temperatures include 93° C., 121° C.,149° C., 177° C. and 204° C. (200° F., 250° F., 300° F., 350° F., 400°F., respectively).

Adhesion Test Procedure

The metal test panel is first cleaned by wiping with a clean cottoncloth moistened with a solvent such as toluene, to remove any oils orresidue from previous tests. The panel is next buffed lightly by handusing Grade “O” steel wool to remove any oxidation and to achieve auniform surface. The freshly buffed panel is cleaned by wiping, using aclean cotton cloth dampened with isopropyl alcohol, to remove anyresidual steel wool, surface oxidation or other residue. Thereafter, thepanel is allowed to condition at room temperature on the counter top fora minimum of 10 minutes before proceeding to apply the test matrix.

Once the panel has conditioned for a minimum of 10 minutes, it is readyfor application of the test matrix. The temperature of the matrix mustbe controlled to +/−5.0° F. (+/−˜2.5° C.) of the applicationtemperature. The application of a straight or nearly straight bead ofmatrix (one must try to avoid laying a bead of matrix that issinusoidal) must be done at a fairly rapid pace in order to achieve theappropriate application temperature. The heated matrix is pressed out ofthe application device and applied to the test panel as a 0.1875″ bead.This can be achieved by holding the panel approximately 2 inches belowthe orifice in the application device, and allowing the bead to lay downon the panel as the panel is moved under the orifice traveling along the12″ length of the panel. The speed of movement of the panel should matchthe speed that the mastic is being pressed out of the application deviceso as to maintain the 0.1875″ diameter. The applied bead should measureapproximately 0.1875″×11.5″ for each test panel. The panel should beheld so that it is horizontal as the bead is being applied. Afterapproximately 11.5″ of mastic has been applied to the panel, the matrixis cut from the application device with a spatula and the panel is setaside to cool, still in the horizontal position. During the application,care must be taken to insure that the matrix bead continuously contactsthe metallic panel, without bridging. If bridging occurs, it mayindicate that the temperature of application should be increased. Thisprocedure is repeated with 3 test panels for each formulation, forrepeatability. Results are reported in triplicate.

Adhesion is determined by rotating the panel by 900 along the axis ofthe bead, so that the bead is required to support its own weight. Thus,in the test procedure, the horizontally disposed surface of the spacer,after application of the matrix, is rotated to a vertical position. Alack of adhesion, or the term not adhering, means that under theforegoing test conditions, at least a portion of the bead applied to thehorizontal test panel releases from the metallic panel under the forceof its own weight when the panel is rotated by 900 so that the surfaceis in a vertical position, as described in the foregoing.

EXAMPLES FOR DISPENSABILITY AND FOGGING TESTS

The following thermoplastic desiccating matrix formulations aredispensable and result in a matrix 132 which has substantially noadhesion to the interior of the spacer 120, and which results in nofogging of the IGU in which it is to be used. Fogging was testing byobserving the heated material in a closed chamber as described in theabove fogging test procedure. Adhesion was tested by the procedure setforth above.

Example 1

SAMPLES I-A I-B I-C (weight in g) (weight in g) (weight in g) FormulaComponent 3A Sieve 100 100 100 13X Sieve 100 100 100 DP 8510 100ESCORENE ® UL7710 100  50 GA 594  50 Test Results Pot Fog Test NONE NONENONE Adhesion Test NO NO NO Dispensing Test YES YES YES

In the foregoing Example I, the Pot Fog Test was performed by the methoddescribed below; adhesion was tested by heating to approximately 130° C.and dispensing from a gun-type hot melt dispenser onto a stainless steelcounter top and observing whether the formulation adhered upon cooling;and the dispensing test was performed in attempting to dispense theformulation for the adhesion test. The material was deemed to pass thedispensing test if it could be melted and discharged from the gun-typehot melt dispentser. DP 8510 is polybutylene from Shell Chemical Co.,having a melt index of 45, when tested by ASTM D-1238, condition E.ESCORENE® UL7710 is 18% EVA. GA 594 is LLDPE.

Example 2

SAMPLE II-A II-B II-C II-D II-E (wt in g) (wt in g) (wt in g) (wt in g)(wt in g) Formula Component ESCORENE ® UL7710 90 105 120 115 140 3ASieve 90  90  90  90  70 13X Sieve 90  90  90  90  70 SUNPAR ® 2280 30 15  0  5  0 Test Results Pot Fog Slight Very NONE Very NONE slightslight Adhesion NO NO NO NO NO Dispensing YES YES YES YES YES

In Example 2, the viscosity of Sample II-D was 440,000 cps at 177° C.(350° F.), and of Sample II-E was 167,000 cps at 177° C. (350° F.). Thetests used for Example 2 were identical to those used for Example 1.

Example 3

The formulation of sample II-E of Example 2 was repeated in a 2600 g.batch. The ESCORENE® UL 7710 was first melted in a Sigma Blade mixer.The molecular sieves were added to the mixer while operating, and thecombined mixture was mixed for about 20 minutes. The viscosity of theformulation was tested in a Brookfield HBT-200 Viscometer with aThermocell and a #29 spindle at various temperatures and RPM, yieldingthe following results.

Brookfield Viscosity Viscosity, Test Temperature RPM Kcps Temp: 178° C.(352° F.)  5 rpm   193 10 rpm   168 20 rpm   170 Temp: 154° C. (309° F.) 2 rpm   480  5 rpm   272 10 rpm   232 20 rpm   140 Temp: 122° C. (251°F.)  1 rpm 2,080  2 rpm 1,920  5 rpm 1,760

Example 4

A further example of the present invention was prepared as follows.

ESCORENE ® MV 02514 1100 g Raven 14 Black   1 g 3A Sieve  825 g 13XSieve  825 g TOTAL 2751 g

The Brookfield viscosity was tested as above with the following results:

Viscosity@177° C. (350° F.)=45,000 cps

Viscosity@121° C. (250° F.)=500,000 cps

EXAMPLE 5

A formulation was prepared containing the following ingredients:

ethylene vinyl acetate copolymer 49.5% by weight molecular sieve (50:50mixture of 3A & 13X) 50.0% carbon black  0.5% TOTAL  100%

In one embodiment, the ethylene vinyl acetate component has a vinylacetate content of less than or equal to 14% by weight. In anotherembodiment, the ethylene vinyl acetate has a vinyl acetate content of20% by weight. In another embodiment, the ethylene vinyl acetatecomponent has a vinyl acetate content of about 10% to about 12% byweight. The formulation, when tested, did not adhere to a metalsubstrate, when applied at a temperature of 120° C., and allowed tocool, followed by testing for adhesiveness as described herein above.

EXAMPLES FOR ADHESION TESTING

The following thermoplastic desiccating matrix formulations wereprepared and tested according to the above described adhesion test. Ineach of the following examples, the desiccant is a mixture of 50 weight% each of 3A and 13X molecular sieve.

 #6: 14% VA Ethylene-Vinyl Acetate Copolymer 50% (ESCORENE ® MVO 2514)Desiccant 50%  #7: 20% VA Ethylene-Vinyl Acetate Copolymer 50%(ESCORENE ® MVO 2520) Desiccant 50%  #8: 28% VA Ethylene-Vinyl AcetateCopolymer 50% (ESCORENE ® MVO 2528) Desiccant 50%  #9: Polybutylene(DP8510) 50% Desiccant 50% #10: Fatty Acid Dimer Polyamide 50% (HenkelVERSAMID ® 757) Desiccant 50% #11: 14% VA Ethylene-Vinyl AcetateCopolymer 25% (ESCORENE ® MVO 2514) Desiccant 50% Hydrogenated RosinEster 25% (Hercules FORAL ® 85) #12: 14% VA Ethylene-Vinyl AcetateCopolymer 45% (ESCORENE ® MVO 2514) Desiccant 50% Hydrogenated RosinEster  5% (Hercules FORAL ® 85) #13: 14% VA Ethylene-Vinyl AcetateCopolymer 15% (ESCORENE ® MVO 2514) Desiccant 50% 121° C. (140° F.) MeltPoint Hydrocarbon Paraffin Wax 35%

#C1 Comparative Example #1: H.B. Fuller Co. INSUL-DRI® HL 5102X; thismaterial is believed to be that described in U.S. Pat. No. 5,510,416.

Test Results

Samples 6-13 and C1 were tested according to the adhesion test describedabove. In all tests, the test panels were electrolytic tin plated steeltest panels (T4 temper, #5 finish); application temperature was 121° C.(250° F.); each test consisted of 3 runs and in each the samples wereallowed to cool to room temperature. “ADHESION LOSS” in these tests isdefined as the cooled test matrix spontaneously detaching from andfalling off the surface to which it was applied in the test, when thesurface is rotated 900, as described above. The following results wereobtained:

FORMULA # TEST RESULT  6 ADHESION LOSS (i.e., NO ADHESION)  7 ADHESIONLOSS  8 NO LOSS OF ADHESION  9 ADHESION LOSS 10 ADHESION LOSS 11 NO LOSSOF ADHESION 12 ADHESION LOSS 13 ADHESION LOSS C1 NO LOSS OF ADHESION

Curable Formulations

In one embodiment, the present invention provides a desiccating matrixformulation comprising a curable polymeric material. In one embodiment,the invention provides a desiccating matrix formulation comprising about80 to about 30 weight % of the formulation of a curable material,wherein the curable material is selected from the group consisting of aone-part blend comprising an isocyanate-terminated prepolymer and aurethane catalyst; a two-part mixture in which a first part comprises ablend of an isocyanate-terminated prepolymer and a urethane catalyst anda second part comprises an active hydrogen compound; and a two-partmixture in which a first part comprises diglycidyl ether bisphenol A anda second part comprises an epoxy curative, for example diethylenetriamine; and about 20 to about 70 weight % of the formulation of anadsorbent component, wherein the adsorbent component includes a moistureadsorbing material and a volatile organic chemical adsorbing material,of which 0-50% of the adsorbent component is the adsorbent of volatileorganic compounds.

The adsorbent component may be mixed into either part of the two partcurable formulations. Preferably, the adsorbent component is mixed intothe first component of each of the two-part mixtures, that is, theisocyanate terminated prepolymer component or the diglycidyl etherbisphenol A component, since the first component is usually the larger.

In one embodiment, the curable material is a one-part blend comprisingan isocyanate-terminated polypropylene glycol prepolymer and dibutyl tindilaurate. In one embodiment of the one-part mixture, theisocyanate-terminated polypropylene glycol prepolymer is BAYTEC™ MP 100,available from Bayer. In this embodiment, the dibutyl tin dilauratecatalyzes the reaction of the isocyanate terminal groups withatmospheric moisture in a cross-linking reaction. In this embodiment, itis not necessary to separate the reactants into the separate componentsof a two-part mixture. In this embodiment, curing is initiated bymoisture in the air surrounding the formulation after it has beenapplied. In this embodiment, the curable material is mixed with theadsorbent component prior to application.

In one embodiment, the one-part blend comprises about 100 parts byweight of an isocyanate-terminated polypropylene glycol prepolymer,about 0.5 parts by weight of dibutyl tin dilaurate and about 100 partsby weight of an adsorbent.

In one embodiment, the curable material is a two-part mixture in which afirst part comprises an isocyanate-terminated prepolymer and a urethanecatalyst and a second part comprises an active hydrogen compound. Thesecond part may also comprise a urethane catalyst if needed. In oneembodiment of the two-part mixture, the first part comprises as theisocyanate-terminated polypropylene glycol prepolymer, BAYTEC™ MP 100,available from Bayer. In one embodiment, the urethane catalyst isdibutyl tin dilaurate which catalyzes the reaction of the isocyanateterminal groups with the active hydrogen compound in a cross-linkingreaction. The active hydrogen compound may be, for example a compoundsuch as polypropylene glycol or 1,4 butanediol. Theisocyanate-terminated prepolymer may be a relatively simplemultifunctional isocyanate when the active hydrogen compound ispolymeric.

Active hydrogen compounds may include alcohols, primary and secondaryamines, organic acids and thiols. In one embodiment, the active hydrogencompound is 1,4-butanediol. In one embodiment, the active hydrogencompound is ethylene glycol. In one embodiment, the active hydrogencompound is 1,6-hexanediol. In one embodiment, the active hydrogencompound is ethylene diamine. In one embodiment, the active hydrogencompound is 1,4-diaminobutane. In one embodiment, the active hydrogencompound is diethylene triamine. When an amine is used, it may not benecessary to add a urethane catalyst. Similarly, when an alcohol such as1,4-butanediol is used, it may not be necessary to add a urethanecatalyst. The active hydrogen compound may be a polymeric material suchas polyethylene glycol or polypropylene glycol.

The urethane catalyst may be any such catalyst known in the art. In oneembodiment, the urethane catalyst is dibutyl tin dilaurate.

In one embodiment, the 1,4 butanediol initiates and participates in thepolymerization reaction when the two parts are combined. In oneembodiment, a first part of the two-part mixture is a blend of about 100parts by weight of a mixture of the isocyanate-terminated polypropyleneglycol prepolymer and about 100 parts by weight of an adsorbent. In oneembodiment, the second part of the two-part mixture is a blend of about10.8 parts by weight of 1,4 butanediol and about 0.5 parts by weight ofdibutyl tin dilaurate.

The following examples 14 and 15 of two-part mixtures in which a firstpart comprises a polymeric active hydrogen compound and a urethanecatalyst and a second part comprises a multifunctional isocyanate.

Example 14

Part A: 100 parts by weight PLURACOL®) 220

 100 parts by weight Desiccant

 0.1 parts by weight dibutyl tin dilaurate catalyst

Part B: 6.4 parts LUPRANATE® M20S

The formulation of Example 14 contains approximately 48.4% desiccant,and is flowable at room temperature. The polymeric active hydrogencompound, PLURACOL® 220, is a polyol available from BASF, having ahydroxyl number of 27, and a molecular weight of about 6000. LUPRANATE®DM20S is a polymeric methylene diisocyanate, having a nominalfunctionality of 2.7, available from BASF. A plasticizer may be added tothe part B component to increase the volume and thus to ease handling ofthe material.

Example 15

Part A: 100 parts by weight PLURACOL® TP440

 100 parts by weight desiccant

 0.1 part by weight dibutyl tin dilaurate catalyst

Part B: 94.9 parts by weight LUPRANATE® M20S

The formulation of Example 15 contains approximately 33.9% desiccant,and is flowable at room temperature. The polymeric active hydrogencompound, PLURACOL® TP440, is a polyol available from BASF, having ahydroxyl number of 398, and a molecular weight of about 400. LUPRANATE®M20S is a polymeric methylene diisocyanate, having a nominalfunctionality of 2.7, available from BASF. A plasticizer may be added tothe part B component, but due to the amount of part B is not necessaryfor handling.

The following additional examples of two-part mixtures in which a firstpart comprises an isocyanate-terminated prepolymer, with no addedurethane catalyst, and a second part comprises an active hydrogencompound are provided. In each case, part A comprises 100 parts byweight of BAYTEC™MP-100 and 100 parts by weight of a molecularsieve-type desiccant, and the active hydrogen compound initiates thepolymerization reaction.

Trade name and chemical Parts by weight Percent description of activeactive hydrogen by weight Example hydrogen compound Supplier compounddesiccant 16 POLAMINE ® 1000 Air 144 29.1% polytetramethyleneoxideProducts di-p-aminobenzoate 17 DETDA Ethyl Corp.   21.4 45.2% diethylenetoluene diamine 18 QUADROL ® BASF   17.5 46.0% N,N,N,N-tetrakis(2-hydroxypropyl) ethylene diamine

Example 19

A further example of a two-part mixture in which a first part comprisesa polymeric active hydrogen compound and a second part comprises amultifunctional isocyanate, in which the active hydrogen compoundinitiates the polymerization in the absence of an added urethanecatalyst, is provided. Part A of the mixture contains 100 parts byweight of POLAMINE™ 1000 brand of polytetramethyleneoxidedi-p-aminobenzoate and 100 parts by weight of a molecular sieve-typedesiccant. Part A is mixed with a Part B which comprises 23 parts ofLUPRANATE® M20S brand of polymeric methylene diisocyanate.

In each of Examples 16-19, the mixture of parts A and B is flowable, butrapidly cures to form a solid desiccating matrix which does not adhereto the surfaces spacers formed of common spacer materials, particularlyaluminum, stainless steel and tin-plated steel.

In one embodiment, the curable material is a two-part mixture in which afirst part comprises diglycidyl ether bisphenol A and a second partcomprises an epoxy curative. In one embodiment, the epoxy curative isdiethylene triamine. In one embodiment, the epoxy curative is acycloaliphatic amine. In one embodiment, the epoxy curative is amodified aliphatic amine. In one embodiment, the epoxy curative is anamide/imidazoline. In one embodiment, the epoxy curative is an amineterminated polyoxypropylene. Any epoxy curative known in the art may beused, so long as the formulation remains flowable until it is applied.In one embodiment, the diglycidyl ether bisphenol A is EPON® 828,available from Shell Chemical Co. In one embodiment, the epoxy curativeis diethylene triamine is EPON® 3223, available from Shell Chemical Co.In one embodiment, the first part of the two part mixture includes about100 parts by weight of diglycidyl ether bisphenol A and about 100 partsby weight adsorbent, and the second part comprises about 12 parts byweight of diethylene triamine. When these two parts are mixed, thecomponents react to form the epoxy polymer.

Additional examples of the two-part mixture in which a first partcomprises diglycidyl ether bisphenol A and a second part comprises anepoxy curative are provided as follows. In each case, 100 parts byweight of the epoxy resin EPON® 828 and 100 parts by weight of amolecular sieve desiccant are combined with the following epoxycuratives:

Parts by Trade name and weight of Percent by Example Chemicaldescription epoxy weight No. of epoxy curative Supplier curativedesiccant 20 EPICURE ® 3382 Shell 63 38.0% Cycloaliphatic amine Chemical21 ANCAMINE ® 163 Air 15 46.5% modified aliphatic amine Products 22ANCAMIDE ® 500 Air 50 40.0% amide/imidazoline Products 23 JEFFAMINE ®D-2 Huntsman 35 42.5% amine-terminated Chemical polyoxypropylene

In each of Examples 20-23, the formulation was flowable immediatelyafter mixing, and the formulation upon curing becomes a soliddesiccating matrix which does not adhere to surfaces of spacers formedof common spacer materials, particularly aluminum, stainless steel andtin-plated steel.

Although the invention has been shown and described with respect tocertain preferred embodiments, equivalent alterations and modificationswill occur to others skilled in the art upon reading and understandingthis specification and the annexed drawings. In particular regard to thevarious functions performed by the above described integers (components,assemblies, devices, compositions, steps, etc.), the terms (including areference to a: means”) used to describe such integers are intended tocorrespond, unless otherwise indicated, to any integer which performsthe specified function of the described integer (i.e., that isfunctionally equivalent), even though not structurally equivalent to thedisclosed structure which performs the function in the hereinillustrated exemplary embodiment or embodiments of the invention. Inaddition, while a particular feature of the invention may have beendescribed above with respect to only one of several illustratedembodiments, such feature may be combined with one or more otherfeatures of the other embodiments, as maybe desired and advantageous forany given or particular application.

What is claimed is:
 1. A method of making a closed hollow spacer for aninsulating glass unit, the method comprising: (1) dispensing a flowabledesiccating matrix formulation onto a portion of the spacer which willbe inside the spacer when the spacer has been closed; (2) allowing orcausing the formulation to solidify into a solid matrix and to detachfrom any attachment to the spacer; (3) closing the spacer whereby thedetached matrix will be retained within the spacer; and (4) retainingthe matrix in the spacer other than by adhesion.
 2. A method as in claim1, wherein the step of dispensing includes heating the formulation to atemperature in the range from about 85° to about 200° C.
 3. A method asin claim 1, wherein the step of dispensing includes heating and pumpingthe formulation in a hot melt pumping apparatus.
 4. A method as in claim3, wherein the step of allowing or causing the formulation to solidifyincludes cooling the formulation prior to the formulation coming intocontact with the spacer.
 5. A method as in claim 1, wherein the spaceris closed following the step of dispensing the formulation.
 6. A methodas in claim 1, wherein the spacer is closed prior to the step ofdispensing the formulation.
 7. A method as in claim 1, further includingthe step of assembling the insulating glass unit by joining at least onespacer and at least two panes of glass.
 8. A method as in claim 7,wherein the step of assembling the insulating glass unit includesproviding an adhesive material between the edge assembly and the panesof glass.
 9. A method as in claim 7, wherein the step of assembling theinsulating glass unit includes providing a sealing material between theedge assembly and the panes of glass.
 10. A method as in claim 1,wherein the desiccating matrix formulation comprises a thermoplasticmaterial.
 11. A method as in claim 1, wherein the desiccating matrixformulation comprises a thermoplastic hot melt material.
 12. A method asin claim 1, wherein the desiccating matrix formulation comprises a wax.13. A method as in claim 1, wherein the desiccating matrix formulationcomprises a tackifier.
 14. A method as in claim 1, wherein thedesiccating matrix formulation comprises a thermosetting material.
 15. Amethod as in claim 1, wherein the desiccating matrix formulationcomprises a two part polymerizable material.
 16. A method as in claim 1,wherein the desiccating matrix formulation is in a liquid form when itis dispensed but solidifies upon contacting the spacer.
 17. A method asin claim 1, wherein the desiccating matrix formulation is in a liquidform when it contacts the spacer.
 18. A method as in claim 1, whereinthe desiccating matrix formulation is in a liquid form when it isdispensed but solidifies prior to contacting the spacer.
 19. A method asin claim 1, wherein the step of dispensing includes pumping a flowable,curable formulation.
 20. A method as in claim 1, further comprising thestep of freeing the matrix from any adhesion to the spacer by applying agentle impact.
 21. A method as in claim 1, wherein the matrix forms noattachment to the spacer.
 22. A method as in claim 1, wherein the matrixforms an initial adhesion to the spacer and upon solidification thematrix loses the adhesion to the spacer.
 23. A method as in claim 1,wherein the matrix forms an initial adhesion to the spacer and uponfurther handling the matrix loses the adhesion to the spacer.
 24. Amethod of making an insulating glass unit including at least two glasspanels and a hollow spacer having an interior wall and separating theglass panels to form an interior space of the IGU, the hollow spacerretaining therein a desiccating matrix, the method comprising: (1)heating a desiccating matrix formulation to a temperature at which it isflowable; (2) dispensing the formulation onto the interior wall of thehollow spacer; (3) allowing the formulation to solidify to form thesolid matrix; (4) freeing the matrix from any adhesion to the spacer;and (5) retaining the matrix in the spacer other than by adhesion.
 25. Amethod as in claim 24, wherein the step of dispensing includes heatingthe formulation to a temperature in the range from about 850 to about200° C.
 26. A method as in claim 24, wherein the step of allowing orcausing the formulation to solidify includes cooling the formulationprior to the formulation coming into contact with the spacer.
 27. Amethod as in claim 24, wherein the spacer is closed subsequent to thestep of dispensing the formulation.
 28. A method as in claim 24, whereinthe spacer is closed prior to the step of dispensing the formulation.29. A method as in claim 24, wherein the desiccating matrix formulationis in a liquid form when it is dispensed but solidifies upon contactingthe spacer.
 30. A method as in claim 24, wherein the desiccating matrixformulation is in a liquid form when it contacts the spacer.
 31. Amethod as in claim 24, wherein the desiccating matrix formulation is ina liquid form when it is dispensed but solidifies prior to contactingthe spacer.
 32. A method as in claim 24, wherein the step of freeing thematrix from any adhesion to the spacer comprises applying kinetic energyby imparting a gentle impact or further handling the spacer duringassembly of the insulating glass unit.
 33. A method as in claim 24,wherein the step of dispensing the desiccating matrix formulationcomprises pumping a curable formulation.
 34. A method as in claim 24,wherein the matrix forms no attachment to the spacer.
 35. A method as inclaim 24, wherein the step of freeing the matrix takes place as a resultof solidification of the matrix.
 36. A method as in claim 24, whereinthe step of freeing the matrix takes place as a result of furtherhandling of the spacer.
 37. A method of making an insulating glass unitincluding at least two glass panels and at least one hollow spacerseparating the glass panels, the panels and spacer forming an interiorspace of the IGU, the hollow spacer retaining therein a soliddesiccating matrix, the method comprising the steps of: (1) heating adesiccating matrix formulation to a temperature at which it is flowable;(2) dispensing the formulation into the hollow spacer under conditionssuch that it forms the solid matrix which does not adhere to the spacerin use; and (3) retaining the matrix in the spacer other than byadhesion.